Remove or replace footer credits (or any text or HTML in page) before page is rendered. With this plugin there is no need to modify code such as footer.php which if done incorrectly can cause your site to break or new theme updates will stomp over your changes requiring you to remove footer credits on each update.
This plugin has very minimal options to keep things simple and easier to use. You enter the text or HTML that you would like to find in one text box and the text or HTML that you would like to replace in another text box (or nothing to remove). Go here to view my step by step tutorial with screenshots and video.